Add User-Agent fallback for Clash subscription imports

2026-07-14 18:48:55 +08:00 · 2026-05-31 18:03:57 +08:00
parent 4b252ee697
commit d85e653307
2 changed files with 158 additions and 27 deletions
@@ -17,6 +17,13 @@ const (
 	clashSubscriptionTimeout  = 25 * time.Second
 )

+var clashSubscriptionUserAgents = []string{
+	"clash-verge/2.0 ant-chrome/1.0",
+	"FlClash/v0.8.92 clash-verge Platform/windows",
+	"clash-verge/v2.4.2",
+	"ClashforWindows/0.19.23",
+}
+
 // BrowserProxyFetchClashByURL 拉取 Clash 订阅 URL，并返回可直接导入的 YAML 文本与建议配置。
 func (a *App) BrowserProxyFetchClashByURL(rawURL string) (map[string]interface{}, error) {
 	rawURL = strings.TrimSpace(rawURL)
@@ -33,36 +40,10 @@ func (a *App) BrowserProxyFetchClashByURL(rawURL string) (map[string]interface{}
 		return nil, fmt.Errorf("仅支持 http/https URL")
 	}

-	req, err := http.NewRequest(http.MethodGet, parsedURL.String(), nil)
-	if err != nil {
-		return nil, fmt.Errorf("创建请求失败: %w", err)
-	}
-	req.Header.Set("User-Agent", "clash-verge/2.0 ant-chrome/1.0")
-	req.Header.Set("Accept", "application/yaml,text/yaml,text/plain,*/*")
-	req.Header.Set("Cache-Control", "no-cache")
-
 	client := &http.Client{
 		Timeout: clashSubscriptionTimeout,
 	}
-	resp, err := client.Do(req)
-	if err != nil {
-		return nil, fmt.Errorf("拉取订阅失败: %w", err)
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		return nil, fmt.Errorf("拉取订阅失败: HTTP %d", resp.StatusCode)
-	}
-
-	body, err := io.ReadAll(io.LimitReader(resp.Body, maxClashSubscriptionBytes+1))
-	if err != nil {
-		return nil, fmt.Errorf("读取订阅内容失败: %w", err)
-	}
-	if len(body) > maxClashSubscriptionBytes {
-		return nil, fmt.Errorf("订阅内容过大（超过 8MB）")
-	}
-
-	content, payload, err := normalizeClashSubscriptionContent(body)
+	content, payload, err := fetchClashSubscriptionWithFallback(client, parsedURL.String())
 	if err != nil {
 		return nil, err
 	}
@@ -84,6 +65,55 @@ func (a *App) BrowserProxyFetchClashByURL(rawURL string) (map[string]interface{}
 	}, nil
 }

+func fetchClashSubscriptionWithFallback(client *http.Client, targetURL string) (string, interface{}, error) {
+	var lastErr error
+	for _, userAgent := range clashSubscriptionUserAgents {
+		content, payload, err := fetchClashSubscriptionWithUserAgent(client, targetURL, userAgent)
+		if err == nil {
+			return content, payload, nil
+		}
+		lastErr = err
+	}
+	if lastErr == nil {
+		lastErr = fmt.Errorf("未配置可用的 User-Agent")
+	}
+	return "", nil, fmt.Errorf("拉取订阅失败: %w", lastErr)
+}
+
+func fetchClashSubscriptionWithUserAgent(client *http.Client, targetURL string, userAgent string) (string, interface{}, error) {
+	req, err := http.NewRequest(http.MethodGet, targetURL, nil)
+	if err != nil {
+		return "", nil, fmt.Errorf("创建请求失败")
+	}
+	req.Header.Set("User-Agent", userAgent)
+	req.Header.Set("Accept", "application/yaml,text/yaml,text/plain,*/*")
+	req.Header.Set("Cache-Control", "no-cache")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", nil, fmt.Errorf("网络请求失败")
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return "", nil, fmt.Errorf("HTTP %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(io.LimitReader(resp.Body, maxClashSubscriptionBytes+1))
+	if err != nil {
+		return "", nil, fmt.Errorf("读取订阅内容失败")
+	}
+	if len(body) > maxClashSubscriptionBytes {
+		return "", nil, fmt.Errorf("订阅内容过大（超过 8MB）")
+	}
+
+	content, payload, err := normalizeClashSubscriptionContent(body)
+	if err != nil {
+		return "", nil, err
+	}
+	return content, payload, nil
+}
+
 func normalizeClashSubscriptionContent(body []byte) (string, interface{}, error) {
 	baseText := strings.TrimSpace(strings.ReplaceAll(string(body), "\r\n", "\n"))
 	if baseText == "" {
@@ -0,0 +1,101 @@
+package backend
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+const testClashSubscriptionYAML = `
+proxies:
+  - name: test-node
+    type: http
+    server: example.com
+    port: 8080
+`
+
+func TestBrowserProxyFetchClashByURLFallbackAfterHTTPStatus(t *testing.T) {
+	var seenUserAgents []string
+	var seenAccept string
+	var seenCacheControl string
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		seenUserAgents = append(seenUserAgents, r.Header.Get("User-Agent"))
+		if len(seenUserAgents) == 1 {
+			seenAccept = r.Header.Get("Accept")
+			seenCacheControl = r.Header.Get("Cache-Control")
+			http.Error(w, "forbidden", http.StatusForbidden)
+			return
+		}
+		fmt.Fprint(w, testClashSubscriptionYAML)
+	}))
+	defer server.Close()
+
+	result, err := (&App{}).BrowserProxyFetchClashByURL(server.URL + "/sub?token=test-token")
+	if err != nil {
+		t.Fatalf("BrowserProxyFetchClashByURL returned error: %v", err)
+	}
+	if got := result["proxyCount"]; got != 1 {
+		t.Fatalf("proxyCount = %v, want 1", got)
+	}
+	if len(seenUserAgents) != 2 {
+		t.Fatalf("request count = %d, want 2", len(seenUserAgents))
+	}
+	if seenUserAgents[0] != clashSubscriptionUserAgents[0] {
+		t.Fatalf("first User-Agent = %q, want %q", seenUserAgents[0], clashSubscriptionUserAgents[0])
+	}
+	if seenUserAgents[1] != clashSubscriptionUserAgents[1] {
+		t.Fatalf("second User-Agent = %q, want %q", seenUserAgents[1], clashSubscriptionUserAgents[1])
+	}
+	if seenAccept != "application/yaml,text/yaml,text/plain,*/*" {
+		t.Fatalf("Accept = %q", seenAccept)
+	}
+	if seenCacheControl != "no-cache" {
+		t.Fatalf("Cache-Control = %q", seenCacheControl)
+	}
+}
+
+func TestBrowserProxyFetchClashByURLFallbackAfterHTMLContent(t *testing.T) {
+	var requestCount int
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		requestCount++
+		if requestCount == 1 {
+			w.Header().Set("Content-Type", "text/html")
+			fmt.Fprint(w, "<html><body>client not supported</body></html>")
+			return
+		}
+		fmt.Fprint(w, testClashSubscriptionYAML)
+	}))
+	defer server.Close()
+
+	result, err := (&App{}).BrowserProxyFetchClashByURL(server.URL)
+	if err != nil {
+		t.Fatalf("BrowserProxyFetchClashByURL returned error: %v", err)
+	}
+	if got := result["proxyCount"]; got != 1 {
+		t.Fatalf("proxyCount = %v, want 1", got)
+	}
+	if requestCount != 2 {
+		t.Fatalf("request count = %d, want 2", requestCount)
+	}
+}
+
+func TestBrowserProxyFetchClashByURLAllFallbackErrorsHideURL(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.Error(w, "forbidden", http.StatusForbidden)
+	}))
+	defer server.Close()
+
+	rawURL := server.URL + "/sub/path?token=secret-token"
+	_, err := (&App{}).BrowserProxyFetchClashByURL(rawURL)
+	if err == nil {
+		t.Fatal("BrowserProxyFetchClashByURL returned nil error, want failure")
+	}
+	errText := err.Error()
+	for _, forbidden := range []string{rawURL, "secret-token", "token=", "/sub/path"} {
+		if strings.Contains(errText, forbidden) {
+			t.Fatalf("error %q leaked %q", errText, forbidden)
+		}
+	}
+}